HTS Coatings — machining & grinding

Chrome Oxide · Titanium Dioxide

55% Cr₂O₃, 45% TiO₂

  • Plasma

Chromium oxide with 45% titanium dioxide is the print-roll and pump-seal workhorse — the coating you pick when pure Cr2O3 is almost right but keeps chipping. A plasma gun melts blended Cr2O3 and TiO2 powder and slams it onto the part in splats that stack into a hard, dense ceramic shell. Vickers hardness lands in the 900-1100 HV window, bond strength runs 4,000-6,000 psi over a NiCrAl tie layer, porosity sits in the low single digits. It grinds with diamond and laps to mirror.

What the 45% TiO2 buys you is toughness. Pure 99% Cr2O3 is harder (1100-1300 HV), but it is brittle — it chips on impact, on thermal cycles, and where the part flexes. The titania fills intersplat voids and gives you a coating that tolerates shock and cleanup without spalling. That is why it owns anilox and impression rolls, mechanical-seal faces, dryer cans, textile thread guides, and slurry-pump internals.

Pick it when pure chrome oxide keeps chipping. Step up to 99% Cr2O3 when the duty is pure low-impact abrasion. Step sideways to WC-Co or Cr3C2-NiCr when the environment turns heavily abrasive with impact, or when service temps climb past 1000°F.

Got an anilox losing cells or a seal face that shattered? Send us the drawing — we'll quote the right Cr2O3-TiO2 blend and finish spec.

Technical data

Hardness
900-1100 HV300 typical APS; Cr2O3-predominant blends sit at the top of that band, TiO2-rich blends closer to 900 HV
Bond strength
4,000-6,000 psi on low-carbon steel with a NiCrAl or Ni/Al bond coat (28-41 MPa); ceramic limitation, not a binder limitation
Max service temp
~1000°F sustained (abrasive wear); ~350-400°F when sealed for wet/corrosive service
Max service temp
~540°C sustained; ~175-205°C sealed wet-corrosive
As-sprayed porosity
2-6% APS (TiO2 blends run denser than pure Cr2O3 — TiO2 melts fully in the plume and fills void networks)
Typical thickness
4-12 mils (100-300 µm) on rolls and seal faces; up to 20 mils on dryer cans and larger cylindrical parts
Surface finish (Ra)
200-400 as-sprayed; 8-20 diamond-ground; 2-6 diamond-lapped/superfinished for seal faces

Where it earns its keep

  • Tougher than pure Cr2O3 — the 45% TiO2 addition plasticizes the plume, fills intersplat voids, and improves fracture toughness so the coating does not chip off under impact or thermal shock the way 99% chromium oxide does
  • Better thermal-shock tolerance than pure chrome oxide — important on anilox rolls washed with hot cleaner, on dryer cans that cycle, and on pump parts seeing flashing-liquid service
  • Slightly easier to grind and finish than 99% Cr2O3 while still holding 900-1100 HV — still a diamond-wheel job, but the wheel life is better and the finish is more forgiving
  • Retains most of pure chromium oxide's abrasion and corrosion performance — chemically inert to most acids, alkalis, and process liquors below ~400°F when sealed
  • Laser-engravable and diamond-lappable to mirror Ra for mechanical-seal faces — the same part can serve print-cell and seal duties depending on finish spec

Where it doesn't

  • Lower hardness than 99% Cr2O3 (900-1100 HV vs. 1100-1300 HV) — pick pure chrome oxide when the duty is pure three-body abrasion and the part will not see impact or thermal cycling
  • Brittle relative to metallic hardfacers (Stellite 6, WC-Co) — do not specify for heavy impact loading, shock, or flexing substrates; ceramics crack, metals yield
  • Service temperature capped near 1000°F — TiO2 undergoes phase transformation above ~1000°F that embrittles the coating, and sealed corrosion duty drops the ceiling to ~400°F; use Cr3C2-NiCr above that

Typical applications

  • Flexographic and gravure anilox and impression rolls (laser-engravable cell structures)
  • Mechanical face seals and pump seal rings
  • Slurry-service pump impellers, casings, and wear rings
  • Papermaking Yankee and can dryers (wear and corrosion shell)
  • Textile thread guides, godet rolls, heater plates, creel bars
  • Plug valves and choke-valve trim in mildly abrasive service
  • Paper-machine doctor-blade surfaces and fiber-contact rolls
  • Cylinder bore liners and sucker-rod couplings where pure Cr2O3 chips on impact

Wear modes addressed

  • Low-stress abrasion (fiber, paper, slurry)
  • Adhesive sliding wear against mechanical-seal faces
  • Fluid and particle erosion
  • Chemical/corrosive wear in wet process service
  • Cavitation erosion in pump internals (secondary)

Industries

  • Printing and packaging (flexo, gravure, label, corrugated)
  • Pulp and paper
  • Textile and synthetic-fiber manufacturing
  • Chemical and petrochemical process
  • Pump and mechanical-seal OEM/MRO
  • Oil & gas (sucker-rod couplings, mildly abrasive trim)
  • Water and wastewater

Substrates

  • Carbon and low-alloy steels (1018, 4140, 4340) with a bond coat
  • Stainless steels (304, 316, 410, 17-4 PH)
  • Gray and ductile cast iron (dryer cans, pump casings)
  • Aluminum bronzes (pump internals, with bond coat)
  • Ni-base alloys for corrosion-critical seal faces

Sources

Data points on this page draw on the following published references. Nothing here replaces a material-specific review by our process engineers — but it's the working starting point.

Material data on this page is provided as a general reference and can vary by lot, substrate, and application. Contact HTS to confirm the right material and specification for your specific part.

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